1. Field of the Invention
The present invention relates to a gap/height difference measurement module for a vehicle and a control method thereof, which detect cross-section data on hemming edges of panels by measuring light sources, even when light, irradiated through the light sources onto vehicle body panels with different colors or with chrome molding, is scattered over the panels, and therefore accurately measure the gap/height difference between the panels of the vehicle body.
2. Description of Related Art
In general, various kinds of panels, such as the roof, hood, doors, and trunk lid, are attached to the body of a vehicle to form the outer appearance of the vehicle body.
Each panel to be attached to the vehicle body should be mounted in such a way as not to produce gaps or height differences with a neighboring panel or the vehicle body. To this end, workers conventionally had to check how well various kinds of panels were mounted, either with a gauge or with the naked eye.
Since the manual gauge check and naked-eye inspection made by workers are dependent upon workers' criteria of quality assessment and their ways of working, it is hard to check accurately whether various kinds of panels are mounted, either correctly or with an error. This leads to low reliability and makes it difficult to provide uniform quality control over vehicle bodies.
To prevent this, automated gap/height difference measurement systems for vehicles are used these days through the method of measuring gaps/height differences between a vehicle body and various kinds of panels with the use of a robot equipped with a camera or sensor.
A gap/height difference measurement module using sensors and light sources is applied to these gap/height difference measurement systems. when light emitted from each light source is irradiated between the panels, the sensors detect straight-line elements from cross sections formed by light through the panels and output them to a controller.
The controller measures the gap/height difference between the panels, based on the horizontal and vertical differences between cross points at curved hemming edges by offsetting the linear axes formed by the straight-line elements output by the sensors.
However, the conventional gap/height difference measurement module as described above has the drawback that, when two panels whose height difference is to be measured have different colors, or one of the panels has chrome molding, the measurement cannot be done with light with the same brightness irradiated from each light source.
As such, while conventional measurement of gaps/height differences between panels having different colors or having chrome molding was done by emitting light of difference brightness from each light source, it has the problems of low measurement accuracy and low measurement reliability, because the light of difference brightness from the panels with different colors or with chrome molding is scattered over the surfaces of the panels, thus making it difficult for the sensors to detect straight-line elements from cross sections formed through the panels by the light of different brightness.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.